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From: eberard@ajpo.sei.cmu.edu (Edward Berard)
Newsgroups: comp.lang.ada
Subject: An Interesting View of "Strong" Vs. "Weak" Typing
Keywords: typing, Ada, Lisp, definitions, evidence
Message-ID: <640@ajpo.sei.cmu.edu>
Date: 3 Jan 90 23:18:13 GMT
List-Id: <comp.lang.ada>

Folks,

I recently posted a large message to comp.object on the evaluation of
object-oriented programming languages. I have received a number of
responses. I would be interested in getting your reaction to the
following quotes from one of respondees:

>>         object-oriented programming. Smalltalk has, in effect, no
>>         types, but there are typed extensions to Smalltalk, e.g.,
>
> Again, CL and Smalltalk have *run-time* types - restrictions on
> the use of *objects* during program *execution*.  Languages such
> as Ada have *compile-time* types - restrictions on the use of
> *identifiers* during program *compilation.*

[...]

>
> More accurately, run-time typing places the burden on the run-time
> system, whereas compile-time typing places the burden on the
> compiler *and* the programmer (who must provide explicit type
> declarations and obey them at all times during program
> development).  I would ask again what solid *experimental*
> evidence anyone has to show that compile-time typing actually
> results in programs more reliable than those possible with
> run-time typing, *in the presence of the requirements evolution
> that is present in any large, complex software project*.

Are there any references documenting the benefits of strong vs. weak
typing? What are your reactions to the definitions given?

				-- Ed Berard
				   (301) 353-9652